Barrel & Grit field manual
How to use a rock tumbler: the first complete batch
A successful first rock-tumbling batch comes from compatible stones, correct barrel fill, measured grit and thorough cleaning between each stage.
Sort the rough
Group stones of similar hardness and remove anything cracked, porous or crumbly. Use a spread of sizes so smaller pieces fill the spaces between larger rocks.
Load the barrel correctly
Most rotary barrels work best around two-thirds to three-quarters full by volume. Add media if needed, then use the water and grit quantities specified for your machine.
Inspect after every stage
Do not advance a rock just because the calendar says seven days have passed. Check the surface, remove damaged pieces and repeat a stage where necessary.
Protect the polish stage
Clean the barrel rim, lid, stones and tools carefully. Final polish rewards the surface preparation already completed; it cannot hide scratches left earlier.